A fuel cell vehicle, which is an environmentally-friendly vehicle, uses a fuel cell to facilitate chemical reactions between hydrogen and oxygen to produce an electricity supply and drive a motor using electricity generated by the fuel cell.
A fuel cell system for a fuel cell vehicle consists of a fuel cell stack for generating electrical energy, a fuel supply device for supplying a fuel (e.g., hydrogen) to the fuel cell stack, an air supply device for supplying oxygen in air that is an oxidant and is required for an electrochemical reaction, and a thermal management system (TMS) that removes reaction heat of the fuel cell stack from the system, controls operating temperature of the fuel cell stack, and performs water and thermal management functions.
The TMS, which is a cooling apparatus that circulates antifreeze or distilled water that acts as a coolant through the fuel cell stack to maintain a temperature (e.g., 60-70° C.), consists of a reservoir for storing the coolant, a pump for circulating the coolant, an ion filter for removing ions from the circulating coolant, and a radiator for lowering temperature of the coolant. The TMS can have a heating, ventilation, and air conditioning (HVAC) heater that performs a vehicle heating function.
The fuel cell system generates electricity by an electrochemical reaction between a fuel (e.g., hydrogen) and oxygen in air, and discharges heat and water that are reaction by-products.
The fuel cell system generates heat that is a reaction by-product, and thus should have a device for cooling the fuel cell stack in order to prevent a temperature rise in the stack. Also, a challenge in the fuel cell system is to ensure cold start ability, and thus the TMS can play an important role. To ensure a cold starting ability, a method for rapidly defrosting the coolant in the fuel cell stack or a method for using stack antifreeze as the coolant is used.
The coolant of the TMS acts as a refrigerant that cools the fuel cell stack. The coolant is rapidly heated by a heater during the cold start, and thus acts as a heating medium that heats the stack quickly.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.